The present invention relates to homokinetic joints of the tripod type and to applications thereof in particular in vehicle wheel hubs.
The invention more particularly relates to homokinetic tripod joints of the type comprising a first element connected to rotate with a tripod element which defines three trunnions on which are rotatably and slidably mounted three spherical rollers, and a second element defining three runways for the rollers, the first element and the second element comprising respectively concave and convex complementary spherical surfaces which cooperate with each other so as to form a ball and socket connection, the rotational connection between the first element and the tripod element constituting in addition an auxiliary homokinetic coupling. Such a joint is described for example in French Pat. No. 77 06 428 filed on Mar. 4, 1977 by the Firm Glaenzer Spicer. These joints may be employed advantageously in automobile vehicle wheel hubs since they are particularly compact and need not be cooled by a current of relative air.
There is also known from French Pat. No. 1,175,941 a joint of the type having a bisecting plane comprising two elements constituting a ball and socket articulation each of which elements is connected to a shaft and in which elements grooves are formed. This joint is completed by a spider having three branches which extend into the grooves of the two elements and are interconnected to pivot about a pin at their inner ends. In this joint, the two elements forming the ball and socket articulation are maintained axially by a coupling of the bayonet type. However, the assembly thereof is complicated because the two elements must be engaged one inside the other in the absence of the branches of the spider which are placed in position only after the fitting together and alignment of the elements, this operation being followed by the placing in position of the pivot pin of the spider which requires, in one embodiment, the provision of a hollow shaft rigid with one of the two elements. Moreover, in such an arrangement, the prevention of relative rotation of the two elements concerned in the bayonet coupling is achieved by the branches of the spider which is possible only in this type of joint where the branches of the spider extend into grooves formed in the inner element and in the outer element.
Such an arrangement has drawbacks in an application such as an automobile vehicle hub and is difficult to manufacture on an industrial scale.